Add bindings to Promise.allSettled

Resolves #5923

Signed-Off-By: Hyeseong Kim <hey@hyeseong.kim>

Author: cometkim

jscomp/others/js_promise2.res

@@ -1,6 +1,10 @@
 type t<+'a> = promise<'a>
 type error
 
+@tag("status")
+type settledResult<+'a> =
+  | @as("fulfilled") Fulfilled({value: 'a}) | @as("rejected") Rejected({reason: unknown})
+
 /** Type-safe t-first then */
 let then: (promise<'a>, 'a => promise<'b>) => promise<'b> = %raw(`
   function(p, cont) {
@@ -52,6 +56,53 @@ external all6: (
   (promise<'a0>, promise<'a1>, promise<'a2>, promise<'a3>, promise<'a4>, promise<'a5>)
 ) => promise<('a0, 'a1, 'a2, 'a3, 'a4, 'a5)> = "all"
 
+@val @scope("Promise")
+external allSettled: array<promise<'a>> => promise<array<settledResult<'a>>> = "allSettled"
+
+@val @scope("Promise")
+external allSettled2: ((promise<'a0>, promise<'a1>)) => promise<(
+  settledResult<'a0>,
+  settledResult<'a1>,
+)> = "allSettled"
+
+@val @scope("Promise")
+external allSettled3: ((promise<'a0>, promise<'a1>, promise<'a2>)) => promise<(
+  settledResult<'a0>,
+  settledResult<'a1>,
+  settledResult<'a2>,
+)> = "allSettled"
+
+@val @scope("Promise")
+external allSettled4: ((promise<'a0>, promise<'a1>, promise<'a2>, promise<'a3>)) => promise<(
+  settledResult<'a0>,
+  settledResult<'a1>,
+  settledResult<'a2>,
+  settledResult<'a3>,
+)> = "allSettled"
+
+@val @scope("Promise")
+external allSettled5: (
+  (promise<'a0>, promise<'a1>, promise<'a2>, promise<'a3>, promise<'a4>)
+) => promise<(
+  settledResult<'a0>,
+  settledResult<'a1>,
+  settledResult<'a2>,
+  settledResult<'a3>,
+  settledResult<'a4>,
+)> = "allSettled"
+
+@val @scope("Promise")
+external allSettled6: (
+  (promise<'a0>, promise<'a1>, promise<'a2>, promise<'a3>, promise<'a4>, promise<'a5>)
+) => promise<(
+  settledResult<'a0>,
+  settledResult<'a1>,
+  settledResult<'a2>,
+  settledResult<'a3>,
+  settledResult<'a4>,
+  settledResult<'a5>,
+)> = "allSettled"
+
 @val @scope("Promise") external race: array<promise<'a>> => promise<'a> = "race"
 
 external unsafe_async: 'a => promise<'a> = "%identity"

jscomp/test/build.ninja

@@ -0,0 +1,9 @@
+let p1 = Js.Promise2.make((~resolve, ~reject) => resolve(1))
+let p2 = Js.Promise2.make((~resolve, ~reject) => resolve("foo"))
+
+switch await Js.Promise2.allSettled2((p1, p2)) {
+| (Fulfilled({value: v1}), Fulfilled({value: v2})) => Js.log2(v1, v2)
+| (Rejected({reason}), Fulfilled(_)) => Js.log2("first rejected", reason)
+| (Fulfilled(_), Rejected({reason})) => Js.log2("second rejected", reason)
+| _ => Js.log("both rejected")
+}